Piggyback load handling crane

ABSTRACT

A crane for transferring a semitrailer, cargo container, or other piggyback load from the road to a rail car, and vice versa, is equipped with parallel horizontal tracks and a load suspension system which is shiftable bodily back and forth on the tracks between the road side and the rail side of the crane. T load suspension system comprises a pair of back and forth movable carriages on the tracts, a load supporting truss between the carriages, and lift arms pivoted on the opposite ends of the truss and bearing at their free ends upon the carriages.

United- S't/a'tes Patent 1:11am Mlrtlnsort [72] Inventor Mllwnulteedtvb. [21] AppLNo. 797,757 {22] Filed Feb. 10, 1969 [45] Patented Aug. 31. 1971 [73] Assigne'e KoehringCornpany Mllwaukee, Wis.

' [54] PIGGYBACK LOAD HANDLING CRANE 2C1a1ms,l0Dr-aw1ng1-lp.

- 2l'2/l8,212/49, 2l4/38,214 /7$ 11 [51] Int. 1166c5/02 [50] F1e1do1Seereh... 212/10-14. l8. 1 24,:l25,40,49;2l4l38, 42.75.7511

[56] mmmcm UNITED STATES PATENTS 2.177.525 10/1939 Henderson 212/11 2.490.609 12/1949 Anderson 212/1'4 3,061,110 I 10/1962 Montgomery earriages.

, Campbell.... 212/13 3.381.826. 5/1968 Durand 212/48 3,396,858 13/1968: Baker 212/13 3,490,622 1/1970 Brackin... 214/75 3,236,400 2/1966 Turturro.. 214/7501) 3,501,027 3/1970 136s., 214/7500 3 1 1 FOREIGN PATENTS; 3 171,527 7/1965 u.s.s.1t...; 212/10 Primary Examiner-Harvey Hornsby Attorneys-William A. Denny, John F. F riedl, Wenzel Zierold,

. Andrew J. Beck and Charles W. Walton ABSTRACT: A crane for transferring a semitrailer, cargo container, or other piggyback load from the-road to a rail car, and -.vice versa, is equipped with parallel horizontal tracks and a load suspension system which is shiftable bodily back and forth on the tracks between the roadside and the rail side of the crane. '1 load suspension system comprises a pair of back and forth movable carriages on the tracts, a load supporting truss between the carriages, and lift arms pivotedon the oppolite ends of the truss and hearing at their free ends upon the s mam--v PATENTEU M1231 12m 3,602,375

sum 1 or 7 BY 4 rramv: v.

, rlccvaxck LOAD IIANDL'INGYCRANE BACKGROUND OF THE IN VENTTON 1. Field of the Invention The invention relates to load handling apparatus and it is concerned more particularly with a crane for handling pig gyback loads, that is, loads such as semitrailers and cargo containers which, in accordance with a widely adopted practice of the shipping industry, are transported by truck for short-haulage and by'rail car forlong haulage.

2. Description of the Prior Art The time between one load pickup and the next, that is, the cycling time of a piggyback load handling crane, should obviously be as short as possible. In this respect, however, difficulties have been encountered during the past. If the load is suspended by cables of a hoist system, as it usually is in heretofore known piggyback load handling cranes, inertia forces due to rapid load handling may cause the load to pendulate, which is undesirable because it makes spotting of the load difficult and prolongs the cycling time.

Another aspect of piggyback loading is the traffic at the railroad yards where trains are to be loaded and unloaded. This involves the maneuvering of semitrailers intoand .out of pickup positions along a train. The preferred practice in this connection is to place the semitrailers upon a paved strip along the track and at. some distance from it so that hauling trucks for the semitrailers may readily move back and forth along the paved strip between a row of parked semitrailers and the train. Further, the semitrailers, when in pickup position,

should stand obliquely with respect to therailroad track, that is, at an acute angle which will make it possible fora :truck to pull out any selected semitrailer from between adjacent trailers without moving the latter. I

To taker care of these requirements gantry-type cranes have been employed during the past. These cranes, however, are

relatively bulky and expensive, and attempts have heretofore been made to provide a platform type crane for thesame -,purpose which would have the advantage of being more compact and less costly than the gantry type. However, such attempts as were made during the past have not, in all respects, been entirely successful.

A relatively wide range of horizontal angularity control of the load is important for the mentioned oblique orientation of the semitrailers in their pickup positions. While platform type cranes, as heretofore known, have been able to turn the load horizontally to some extent, they have not been adequate to afford the relativelywiderange of angularity which isirequired for the most efficient selective handling of semitrailers from a parked row along a railroad train.

Another shortcoming of side loading cranes, as heretofore suggested, has been that it wasdifficult tofullysafeguard their lateral stability under adverse operating conditions as, for instance, under crosswinds or under inertia forces set up by rapidload transfer from one side. of the crane to theother.

SUMMARY OF THE INVENTION Generally it is an object of the invention 'to provide an improved platform type piggyback load handling crane.

More specifically, it is an object of the invention toprovide an improved platform type crane which will be -'capable of transferring a piggyback load from the road to arail-car, or vice versa, rapidly but without causing the load to'pendulate at theend of the transfer operation.

A further object of the invention is to provide a piggyback load'handling crane having a platform type mobile chassis and an overhead load suspens'ionsystem which will provide arelatively wide range of horizontal angularity control of the load.

A still further object of the invention is to,provide-an:improvedplatfonn type crane incorporatinga relatively simple and highly efiicientcounterbalancing system for its load han-' dling mechanism.

These and other objects and advantages will be apparent from the description herein of a preferred embodiment of the invention illustrated by the accompanying drawings, wherein FIG. 1 is a side elevation of a platform type piggyback load handling'crane; the crane being shown in full lines in a load pickup condition, and in broken lines in an intermediate load lifting condition;

7 FIG. 2 is a view similar to FIG. 1 andshows the crane in a maximum load lifting condition;

FIG. 3 is an end view on line Ill-III of FIG. 1 and shows a piggyback load in full lines at the road side and in broken lines at the rail side of the crane;

FIG. 4 is a sectional view taken on line IV-IV of FIG. 2;

FIG. 5 is a top view of FIG. 1 and of part of a rail car and a railroad track;

FIG. 6 is a view similar to FIG. 5 and shows the overhead assembly of the crane in an oblique position.

FIG. 7 is an enlarged elevational view of a carriage and counterweight;

FIG. 8 is a top view ofFIG. 7;

FIG. 9 is an enlarged elevational view partly in-section, showing parts at one end of the crane; and

FIG. 10 is an enlarged detail view of an articulated joint as sembly.

The principal components of the crane shown in the drawings are: a mobile chassis generally designated by the reference character 1; opposite end assemblies on the chassis generally designated by the reference characters 2 and 3, respectively; and an overhead assembly spanning the end assemblies and generally designated by the reference character 4 The'mobile chassis l'comprises a horizontal, longitudinal main beam 5 mounting laterally extending horizontal frame work '6, a.front axle 7 supported on steerable, power driven front wheels 8 and 9; area! axle 11 supported on steerable, power driven rear wheels 12 and l3,'and transverse front and rear box frames 14 and l6-secured to the front and rear ends, respectively, of the main beam '5.

The 'mobile chassis is stabilized against lateral tilting by ground engaging, laterally projectable and retractable front -outriggers 17, 18, and rear outriggers 19, 21 of conventional transverse and inclined cross braces 26. The upper ends of the post assembly22 are pinconnected at 27 and 28 to depending lugs-sat one side of a downwardly tapered boxpart 29, and the upper'ends'of the;post'assembly 24 are similarlyconnected to the other side of the box part 29.

The post assemblies 22,. 24 and associated bracing .26, together with'the box part 29 form the stern portion of .the T- shapedrear'support on:the;chassis l. The top part of the T is *formedby a long =hollow'crossbeam 31 of substantially-square cross section. The box part 29 of the stem has upwardly .diverging'sides 32 and 33.and.it is integrally connected, as by welding along its top edges, withthe lower side of the crossbeam 31.

The T-shaped support-comprising thepost assemblies 22,

.24,lbracing.26, box part 29 and .crossbeam 31 is normally 'securedagainst forwardorbackwardpivoting on the rear box sframe l6-by abrace 34 offixed length. One end of the brace 34 is pin connected at 36'with-the 'main beam 5 ofthe chassis 1,'and the'other endof-the brace is pin connected'to-thebox part 29. The'crossbeam 31 mounts-a pair of parallelrails'37, 38 (-FIG.'9)-on its upper side on which a carriage, generally designated by. the reference character 39, is movable back and forth transversely of the chassis 1, as will be described more fully hereinbelow. For purpose of dismantling the crane the unit comprising the box part 29 and crossbeam 31 may readily be removed from the chassis by means of an auxiliary crane after the box part 29 has been disconnected from the upper ends of the post assemblies 22, 24 and from the upper end of the brace 34.

The forward end assembly 3 on the chassis 1 includes a T- shaped support which is an opposite hand duplicate of the T- shaped support of the rearward end assembly 2. Primed reference numerals corresponding to the unprimed reference numerals for the parts of the T-shaped support at the rear designate the same parts of the T-shaped support at the front end of the mobile chassis 1. A carriage 39 which is an opposite hand duplicate of the carriage 39 is movable back and forth transversely of the chassis 1 on rails 37', 38' of the T- shaped support at the front end of the chassis.

In lieu of the solid brace 34 which secures the rearward T-- shaped support in an upright position on the chassis 1, a telescopic link 41 has a pivotal connection 42 at its lower end with the main beam 5 of the chassis, and the upper end of the link 41 has another pivotal connection with the box part 29' of the forward T-shaped support. The relatively reciprocable elements of the brace 41 are normally free to telescope. For purposes of dismantling the crane or erecting it a lockup pin, not shown, may be inserted through registering holes 43 in the upper and lower parts of the brace 41 so that the forward T- shaped support will be temporarily secured in the upright position in which it is shown in full lines in FIG. 1.

The overhead assembly 4 between the end assemblies 2 and 3, as best shownin FIG. 2, comprises a truss 44; a rear lift arm 46 pivoted at 47 on the rear end of the truss and bearing at its free end upon the carriage 39; a front lift arm 46' pivoted at 47 on the front end of the truss and bearing at its free end upon the carriage 39'; rear and front crane trolleys 48, 48' on the truss; and rear and front pairs of grapple arms 49, 51, (FIG. 3), and 49', 51' (FIG. 4) suspended from the trolleys 48 and 48', respectively.

The truss 44 is of lattice type construction and of uniform width from end to end (FIG. 5). The height of the truss is uniform at an elongated midportion (FIG. 1) and diminishes gradually at its opposite ends. As shown in FIG. 4, the truss comprises tubular top beam 52, 53 and tubular bottom beams 54, 56 which extend parallel to each'other in the longitudinal direction of the truss and are interconnected by transverse braces 57 (FIG. 5) and vertical lacing 58 (FIG. 1).

The lift arm 46 is best illustrated by FIGS. 7, 8 and 9. It comprises a pair of relatively long, parallel side beams 59, 61; a cross tube 62, to which the beams 59, 61 are secured, as by welding, so as to extend radially therefrom in transverse alignment with each other; and a pair of relatively short parallel extension plates 63, 64 which are secured, as by welding, to the opposite end faces of the cross tube 62 so as to extend radially therefrom in transverse alignment with each other and in downward inclined relation to the beams 61, 62. The free ends of the beams 59, 61 are pivotally connected at 47 on a horizontal transverse axis with the rear end of the truss 44.

Up and down adjustment of the lift arm 46 about its pivot axis 47 iseffected by two hydraulic rams 66, 67 which are mounted on the truss 44 on a common transverse pivot axis 68 above the pivot axis 47, the ram 66 having a pivot connection 69 (FIG. 9) with the side beam 59 of the lift arm 46, and the ram 67 having a corresponding pivot connection with the side beam 61.

Midway between the extension plates 63, 64 of the lift arm 46 a third extension plate 71 is secured to the cross tube 62, the free ends of the extension plates 63, 64, 71 being transversely aligned with each other on an axis 72 (FIG. 9), which extends parallel to and is spaced radially from the cross tube 62. In the assembled condition of the crane, as shown in FIG. 1, the cross tube 62 and the extension plates 63, 64, 71 overlie the carriage 39 and are connected in load transmitting relation thereto. The carriage comprises a horizontal frame including longitudinal side members 73, 74 (FIG. 8), end crossmembers 76, 77 and intermediate crossmembers 78, 79. Pairs of double flanged wheels 81, 82 and 83, 84 support the carriage frame at its opposite ends on the rails 37 and 38. The flanges of the wheels 81 and 83 straddle the rail 38, and the flanges of the wheels 82 and 84 straddle the rail 37 so that horizontal thrust forces acting in the longitudinal direction of the mobile chassis 1 will be transmitted from the T-shaped support of the end assembly 2 to the carriage 39, and vice versa.

A vertical load transmitting shoe 86 is pivotally mounted on the axis 72 at the free end of the extension plate 63 and a similar shoe 87 is pivotally mounted on the axis 72 at the free end of the extension plate 64. The shoes 86, 87 slidably bear upon the end members 76, 77 of the rear carriage 39. In FIG. 9 the end member 76 is shown inclined relative to the top surface of the crossbeam 31, and the end member 77 is similarly inclined, to compensate for the slight backward tilt at which the T-shaped support of the rear end assembly 2 is normally positioned as shown in F IG. 1.

The connection between plate 71 and the carriage 39 is shown in detail in FIG. 10. It comprises a yoke 88 and a selfaligning ball bushing 89. A pivot pin 91 for the yoke 88 is mounted on the crossmembers 78, 79 of the carriage frame, and a pin 92 on the swinging end of the yoke mounts the inner ring 93 of the ball bushing 89. The outer ring 94 of the ball bushing is fitted into a circular bore at the free end of the extension plate 71. Retainer rings 96, 97 bear against the axially opposite ends of the outer ball ring 94 and are secured to the plate 71 by screws 98. The inner ball ring 93 is centered between the arms of the yoke 88 by tubular spacers 99.

The ball bushing 89 and associated parts, in conjunction with the slide shoes 86, 87, afford an articulated joint between the lift arm 46 and the carriage 39 which accommodates up and down movement and horizontal angular displacement of the lift arm 46 relative to the carriage 39. At the other end of the lift arm 46 the pivot connections of the side beams 59, 61 with the rear end of the truss 44 of the axis 72 afford a hinge joint which connects the lift arm 46 in up and down swingable relation with the truss.

A mechanism for moving the carriage 39 on the rails 37, 38 from one end of the crossbeam 31 to the other, and vice versa, is shown in FIGS. 7, 8 and 9. It comprises a cable 101 which is wrapped around a driving drum 102 on the frame of the carriage 39, and which is anchored at its opposite ends on the crossbeam 31, one end of the cable having a plug 103 which is bolted to one end of the beam 31, and the other end of the cable having another plug, not shown, which is bolted to the other end of the beam 31. A reversible hydraulic motor 104 on the carriage 39 drives a speed reducing transmission 106 which has a two-way driving connection with the drum 102. Rotation of the drum in opposite directions causes back and ,forth movement of the carriage 39 along the top of the T- shaped support at the rear end of the chassis 1.

Reciprocably mounted within the crossbeam 31 is a counterweight 107 which is supported on four wheels 108. Running shoulders 109 F IG. 9) for the wheels 108 extend along the inside bottom wall of the beam 31 throughout its length. Power transmitting means operatively connecting the counterweight 107 with the carriage 39 comprise two cables 111 and 112, one for pulling the counterweight to the right in FIG. 7 when the carriage 39 moves to the left, and the other for pulling the counterweight to the left when the carriage moves to the right.

As shown in FIG. 9, the carriage 39 has depending brackets 113 and 114 at its opposite sides, and rollers 116, 117 at the lower ends of the brackets 113 and 114 underlie overhanging flange portions of the rails 37, 38. The carriage will thus be counterweight 107, as viewed in FIG. 7. Similarly, a turnbuckle 122 is connected at one end with the bracket 114 and at its other end with the cable 112. From the turnbuckle 122 the cable 112 extends around a sheave 123 (FIG. 5) at the left end of the beam 31, and a plug 124 (FIG. 8) at the other end of the cable 112 is bolted to the left end of the counterweight 107, as viewed in FIG. 8. The cables 111 and 112 are so dimensioned in length that adjustment of the carriage 39 to its center position between the ends of the beam 31 will also place the counterweight 107 into a center position between the ends of the beam 31. Movement of the carriage 39 along the crossbeam 31 in one direction will automatically move the counterweight 107 in the opposite direction, and when the carriage 39 has travelled to one end of the beam 31 the counterweight 107 will have travelled to the other end, and vice versa.

The front end of the truss 44 has a lift connection with the T-shaped support of the front end assembly 3, which is in all respects identical with the hereinbefore described lift connection of the rear end of the truss with the T-shaped support of the rear end assembly 2. Primed reference numerals corresponding to the unprimed reference numerals for the rearward lift connection designate the same parts of the forward lift connection.

Upward swinging of the lift arms 46, 46 about their pivot axes 47, 47' by full contraction of the lift rams 66, 67 and 66', 67' lowers the truss into the load pickup position in which it is shown in full lines in FIG. 1.

Expansion on the rarns 66, 67 and 66', 67' from their fully contracted conditions raise the truss and also increases the relative spacing between the carriages 39, 39' in the longitudinal direction of the chassis. As a result, the front end assembly 3 will be tilted forward from the full line position in which it is shown in FIG. 1; and a position of maximum forward tilt will be attained when the truss has been raised to the intermediate position in which it is shown in broken lines in FIG. 1. Continued expansion of the lift rams 66, 67 and 66', 67 which raises the truss from the intermediate position to the load transfer position illustrated by FIG. 2 causes the front end assembly 3 to tilt back to the upright position in which it is shown in FIG. 2, and which is substantially the same as in FIG. 1.

The forward crane trolley 48' on the truss 44 comprises a frame which, as shownin FIG. 4, surrounds the truss and is supported thereon for sliding movement in lengthwise opposite directions. Angle iron members 126, 127 (FIG. 4) at opposite sides, respectively, of the trolley have horizontal flanges overlying the top beams 52 and 53 of the truss, and a cross tube 128 underlying the truss 44 is connected with depending flanges of the angle irons 52, 53 by brace assemblies 129 and 131.

A double acting hydraulic shift ram 132 for the trolley 48' is connected at its barrel end with a bracket 133' at the upper side of the trolley, and the piston rod of the shift ram 132' is connected with a bracket 134 at the upper side of the truss 44. Contraction of the shift ram 132 moves the trolley 48' to its forward end position on the truss in which it is shown in FIGS. 1 and 2, and expansion of the shift ram 132 moves the trolley to a rearward end position. I

The cross tube 128 of the trolley 48 shiftably supports the forward grapple arms 49 and 51' for translatory horizontal movement toward and away from each other; and the cross tube 128 also supports the grapple arms 49 and 51 for pivotal movement at right angles to their translatory movement. In order to provide for such translatory and pivotal movement of the grapple arms, elongated tubular side journals 136, 137 (FIG. 4) are connected, respectively, to the grapple arms at their upper ends, and are telescopically and rotatably supported within the opposite end portions of the tube 128.

Actuating means for the grapple arm 49' comprise a double acting hydraulic shift ram 138 within the cross tube 128, and a double acting hydraulic swing ram 139' at the same side of the trolley 48 as the grapple arm 49'.

The shift ram 138 is anchored at its barrel end on a vertical pin within the tube 128 adjacent the longitudinal vertical midplane of the truss, and the piston rod of the ram is connected to the inner end of the journal 136. Contraction of the ram 138 adjusts the grapple arm 49' to its limit of translatory inward movement as shown in full line in FIG. 4, and expansion of the ram 138 adjusts the grapple arm 49' to its limit of translatory outward movement as shown in broken lines in FIG. 4.

The swing ram 139 is universally connected at its barrel end with a bracket arm 141 of the brace assembly 129 and the piston rod of the swing ram is universally connected with the grapple arm 49 at a radial distance from the axis of the tubular journal 136. Contraction of the swing ram 139 lowers the grapple arm 49' to the vertical position in which it is shown in FIG. 1 irrespective of the lateral position to which the grapple arm is adjusted by the shift ram 138. Conversely, expansion of the swing ram 139 raises the grapple arm 49 to the approximately horizontal broken line position in which it is shown in FIG. 1, regardless of its lateral adjustment by the shift ram 138.

A shift ram 49'. corresponding to the shift ram 138, and a swing ram 143 corresponding to the swing ram 139' are connected to the tubular journal 137 and to the grapple arm 51' for translatory shifting and vertical swinging of the latter relative to the crane trolley 48', the same as the grapple arm 49.

The foregoing explanations with respect to the front trolley 48', analogously apply to the rear trolley 48. A shift ram 132 is connected at its opposite ends to brackets 133 and 134 on the rear trolley frame and on the truss 44, for shifting the rear trolley 48 back and forth longitudinally on the truss. Shift and swing rams for the grapple arms 49, 51 on the rear trolley 48 areduplicates of the shift rams 138, 142 and 139', 143' on the front trolley, the swing ram 139 corresponding to the swing ram 139 being shown in FIG. 2.

An operators cab 144- (FIGS. 1 and 2) is'mounted at the rear end of the chassis 1, and it will be understood that the chassis also carries a power plant, not shown, including an internal combustion engine, hydraulic pumps and associated hydraulic circuits for actuating hydraulic motors of the chassis running gear and of various other components of the crane. A control console in the cab 144 with the necessary hydraulic valves, not shown, enables an operator in the cab to conveniently perform and observe all functions of the crane.

A semitrailer 146 of conventional construction is shown in FIG. 1 positioned on a pavement strip which may extend along a railroad track 147, shown in FIGS. 3 and 5. In FIG. 5 the semitrailer extends parallel to the railroad track, and the crane chassis l with the wheels 9-13 is located between the semitrailer 146 and a flat car 148 on the railroad track 147. The transverse spacing of the semitrailer from the track is also sufficient to permit adjustment of the front outriggers 17, 18 and rear Outriggers 19, 21 to their fully extended positions in which they bear upon the pavement at substantial lateral distances beyond the tread spacing of the crane front supporting wheels 8, 9 and beyond the tread spacing of the crane rear supporting wheels 12, 13.

In order to pick up the semitrailer 146 from the position in which it is shown in FIGS. 1, 3 and 5, the overhead assembly 4 of the crane is first manipulated into the position in which it is shown in FIGS. 1 and 3 and in which the front and rear grapple arms 49', 51' and 49, 51 straddle the body of the semitrailer and grip it as shown in full lines in FIG. 4. Pressure fluid is then admitted to the rear lift rams 66, 67 and front lift rams 66', 67' so that they will expand and cause the overhead assembly 4 and semitrailer 146 to assume the raised position at the roadside of the crane in which they are shown in FIG. 2. In that condition of the crane the counterweights 107, 107 will be positioned at the railside of the crane and substantially balance the weight of the overhead assembly 4..

Next, the hydraulic motor 104 on the carriage 39 and the corresponding hydraulic motor on the carriage may be energized to transfer the truss and semitrailer to the railside of the crane and into a position from which the semitrailer may be lowered straight down upon the flat car 148 on the railroad track 147. Such transfer may be effected rapidly, and when the carriages are stopped at the end of the run the semitrailer will stop instantaneously without pendulating because of its laterally rigid connection with the carriages by means of the grapple arms, trolleys and lift arms 46, 46.

The flat car 148 has a stanchion 149 and the semitrailer 146 has a coupling stud 151 which may be engaged with the stanchion when the semitrailer is lowered upon the flat car. The shift rams 132, 132' on the truss 44 may be adjusted to manipulate the semitrailer into a rearwardly shifted position before it is lowered by contraction of the lift rams 66, 67 and 66', 67'; and after the wheels of the semitrailer have come to rest on the flat car the shift rams 132, 132' may be activated to shift the trailer forward and thereby engage the coupling stud 151 with the stanchion 149. The stud may then be locked on the stanchion by means of a suitable latch mechanism, not shown.

After the semitrailer has been lowered upon the flat car the grapple arms 49, 51 and 49, 51' are disengaged from it by expansion of the shift rams 138, 142 as indicated in broken lines in FIG. 4, and by expansion of the swing rams as indicated in broken lines in FIG. 1. Thereafter the overhead assembly 4 may be raised slightly and moved back to the road side of the crane for a new pickup.

Unloading a semitrailer from a flat car may obviously be accomplished by reversing the described loading procedure, except that in bringing a semitrailer from the railside to the roadside of the crane the semitrailer may be maneuvered into an oblique position as illustrated by FIG. 6 by correspondingly controlling the travel of the carriages 39, 39'. Depositing the semitrailers obliquely, that is, at a substantial horizontal angle relative to the railroad track is a well-known expedient and a common requirement in the handling of piggyback loads. When a row of semitrailers are parked obliquely side by side along the railroad track a hauling truck may move into the space between the track and the trailers and be coupled to any selected one of them and pull it out of the row without moving any of the adjacent semitrailers.

In the herein disclosed crane the requirement for a relatively wide range of horizontal angular adjustment of a semitrailer or other piggyback load suspended from the truss 44 is afforded by the articulated connections of the lift arms 46, 46'

with their respective carriages 39, 39 and by the back and forth tiltable mounting of the T-shaped support of the front end assembly 3.

It is claimed and desired to secure by Letters Patent:

l. A crane adapted to laterally transfer a load from one side of the crane to the other, said crane comprising:

a mobile chassis having longitudinal ends;

a pair of generally T-shaped supports each having a vertical post assembly with a horizontal crossbeam fixed adjacent the upper end of said vertical post assembly;

first and second mounting means for mounting the lower ends of said post assemblies in an upstanding position adjacent said chassis ends in a spaced, generally parallel relation to each other with said crossbeams extending traversely of the longitudinal axis of said chassis, one of said mounting means including pivotal means for pivotally mounting one of said T-shaped supports on one of said chassis ends;

a motor means for moving one of said T-shaped supports about its pivot;

an overhead assembly spanning said support comprising:

first and second carriages operatively mounted, respectively, on each of said crossbeams for horizontal movement traversely of said chassis; a generally horizontally extending load carrying truss operatively connected to said carriages; first and second lift means operatively interposed, respectively, between said first carriage and one end of said truss in vertical and horizontal load transmitting relation to said first carriage and between said second carnage and the other end of said truss in vertical and horizontal load transmitting relation to said second carriage, said first and second lift means each comprising a lift arm, a hinge joint at one end of said lift arm and an articulated joint at the other end thereof; a power cylinder connected between said truss and lift arm to provide up and down movement to said truss, articulated hinge joints connecting said lift arm with opposite ends, respectively, of said truss in up and down swingable relation thereto, and said articulated joints being associated, respectively, with said first and second carriages and operative to accommodate up and down movement and horizontal angular displacement of said lift arms relative to said carriages 2. A crane according to claim 1 further comprising a pair of counterweights mounted, respectively, on said supports for back and forth movements traversely of said chassis, and power transmitting means operatively connecting said counterweights, respectively, with said carriages so that movement of said carriages in one direction causes movement of said counterweights in the opposite direction, and vice versa. 

1. A crane adapted to laterally transfer a load from one side of the crane to the other, said crane comprising: a mobile chassis having longitudinal ends; a pair of generally T-shaped supports each having a vertical post assembly with a horizontal crossbeam fixed adjacent the upper end of said vertical post assembly; first and second mounting means for mounting the lower ends of said post assemblies in an upstanding position adjacent said chassis ends in a spaced, generally parallel relation to each other with said crossbeams extending traversely of the longitudinal axis of said chassis, one of said mounting means including pivotal means for pivotally mounting one of said Tshaped supports on one of said chassis ends; a motor means for moving one of said T-shaped supports about its pivot; an overhead assembly spanning said support comprising: first and second carriages operatively mounted, respectively, on each of said crossbeams for horizontal movement traversely of said chassis; a generally horizontally extending load carrying truss operatively connected to said carriages; first and second lift means operatively interposed, respectively, between said first carriage and one end of said truss in vertical and horizontal load transmitting relation to said first carriage and between said second carriage and the other end of said truss in vertical and horizontal load transmitting relation to said second carriage, said first and second lift means each comprising a lift arm, a hinge joint at one end of said lift arm and an articulated joint at the other end thereof; a power cylinder connected between said truss and lift arm to provide up and down movement to said truss, articulated hinge joints connecting said lift arm with opposite ends, respectively, of said truss in up and down swingable relation thereto, and said articulated joints being associated, respectively, with said first and second carriages and operative to accommodate up and down movement and horizontal angular displacement of said lift arms relative to said carriages.
 2. A crane according to claim 1 further comprising a pair of counterweights mounted, respectively, on said supports for back and forth movements traversely of said chassis, and power transmitting means operatively connecting said counterweights, respectively, with said carriages so that movement of said carriages in one direction causes movemenT of said counterweights in the opposite direction, and vice versa. 